1. The Field of the Invention
The present invention relates generally to the field of pipe fittings. More particularly, it concerns a one piece tubular elbow fitting made from existing plastic pipe.
2. The Background Art
Polyvinyl chloride is a white, water-insoluble thermoplastic material, commonly referred to as PVC, which is often used to make pipe and pipe fittings. PVC pipe is rigid and lightweight, and is often used in the construction of water and sewer systems. The associated pipe fittings such as tees, elbows and the like are typically made from PVC material by injection molding processes and fabrication. Some 90-degree elbow fittings are injection molded directly, while others are made by fastening together two thermoformed or fabricated 45-degree elbows in an end-to-end configuration.
The prior art PVC elbows are characterized by a number of disadvantages..The injection molding process can be expensive and time-consuming, and does not produce a PVC fitting having maximum strength. While the injection molded fitting can provide a one-piece 90-degree elbow with a standard radius, the flow characteristics are downgraded in comparison to an elbow with a long radius. The method of fastening elbow fittings end-to-end produces a seam in the flow channel which introduces bumps and/or grooves at an inner surface of the fitting, thereby increasing friction and head loss. Of current interest are one-piece PVC elbow fittings having increased strength, seamless side walls, and providing flow characteristics of a long radius elbow while having an overall radius similar to a standard 90-degree elbow, and methods of making the same.